. >>> fbi investigators want to know what caused a massive explosion that killed two and damaged over 30 homes, while leveling some completely. good morning to you. i'm veronica de la cruz. government officials say after admitting that an extramarital affair with his biographer paula broadwell. a woman received harassing e-mails from broadwell. and the complaint led to the investigation that uncovered the affair. there's a growing chorus of questions from lawmakers as to when exactly the affair came to light, who in washington knew about it and when they were told. >> reporter: according to a senior federal official and close friend of david petraeus, 37-year-old jill kelly complained to fbi agents about being harassed by paula broadwell, david petraeus' biographer. a senior military official says jill kelly is involved in wounded warrior fund raising in tampa, is married. she and her husband are close petraeus family friends. officials say petraeus' downfall started when kelly was receiving harassing e-mails from broadwell. those e-mails led to the discover of mothers between general